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lib/uzlib/defl_static: Optimize zlib_start/finish_block.

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Collapsing the two adjacent calls to outbits saves 32 bytes.

Bringing defl_static.c into lz77.c allows better inlining, saves 24 bytes.

Merge the Outbuf/uzlib_lz77_state_t structs, a minor simplification that
doesn't change code size.

This work was funded through GitHub Sponsors.

Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
This commit is contained in:
Jim Mussared 2023-06-27 02:56:58 +10:00 committed by Damien George
parent ef5061fefd
commit 7f16bfca9f
4 changed files with 44 additions and 80 deletions
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49
lib/uzlib/defl_static.c
View File

@ -52,15 +52,15 @@ WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
* having to transmit the trees.
*/
static void outbits(struct Outbuf *out, unsigned long bits, int nbits)
static void outbits(uzlib_lz77_state_t *state, unsigned long bits, int nbits)
{
assert(out->noutbits + nbits <= 32);
out->outbits |= bits << out->noutbits;
out->noutbits += nbits;
while (out->noutbits >= 8) {
out->dest_write_cb(out->dest_write_data, out->outbits & 0xFF);
out->outbits >>= 8;
out->noutbits -= 8;
assert(state->noutbits + nbits <= 32);
state->outbits |= bits << state->noutbits;
state->noutbits += nbits;
while (state->noutbits >= 8) {
state->dest_write_cb(state->dest_write_data, state->outbits & 0xFF);
state->outbits >>= 8;
state->noutbits -= 8;
}
}
@ -81,18 +81,18 @@ static int int_log2(int x) {
return r;
}
void zlib_literal(struct Outbuf *out, unsigned char c)
static void uzlib_literal(uzlib_lz77_state_t *state, unsigned char c)
{
if (c <= 143) {
/* 0 through 143 are 8 bits long starting at 00110000. */
outbits(out, mirrorbyte(0x30 + c), 8);
outbits(state, mirrorbyte(0x30 + c), 8);
} else {
/* 144 through 255 are 9 bits long starting at 110010000. */
outbits(out, 1 + 2 * mirrorbyte(0x90 - 144 + c), 9);
outbits(state, 1 + 2 * mirrorbyte(0x90 - 144 + c), 9);
}
}
void zlib_match(struct Outbuf *out, int distance, int len)
static void uzlib_match(uzlib_lz77_state_t *state, int distance, int len)
{
assert(distance >= 1 && distance <= 32768);
distance -= 1;
@ -133,9 +133,9 @@ void zlib_match(struct Outbuf *out, int distance, int len)
* 11000000.
*/
if (lcode <= 22) {
outbits(out, mirrorbyte((lcode + 1) * 2), 7);
outbits(state, mirrorbyte((lcode + 1) * 2), 7);
} else {
outbits(out, mirrorbyte(lcode + 169), 8);
outbits(state, mirrorbyte(lcode + 169), 8);
}
/*
@ -144,7 +144,7 @@ void zlib_match(struct Outbuf *out, int distance, int len)
if (thislen < 255 && x > 1) {
int extrabits = x - 1;
int lmin = (thislen >> extrabits) << extrabits;
outbits(out, thislen - lmin, extrabits);
outbits(state, thislen - lmin, extrabits);
}
x = int_log2(distance);
@ -153,7 +153,7 @@ void zlib_match(struct Outbuf *out, int distance, int len)
/*
* Transmit the distance code. Five bits starting at 00000.
*/
outbits(out, mirrorbyte((x * 2 + y) * 8), 5);
outbits(state, mirrorbyte((x * 2 + y) * 8), 5);
/*
* Transmit the extra bits.
@ -161,20 +161,21 @@ void zlib_match(struct Outbuf *out, int distance, int len)
if (x > 1) {
int dextrabits = x - 1;
int dmin = (distance >> dextrabits) << dextrabits;
outbits(out, distance - dmin, dextrabits);
outbits(state, distance - dmin, dextrabits);
}
}
}
void zlib_start_block(struct Outbuf *out)
void uzlib_start_block(uzlib_lz77_state_t *state)
{
// outbits(out, 0x9C78, 16);
outbits(out, 1, 1); /* Final block */
outbits(out, 1, 2); /* Static huffman block */
// Final block (0b1)
// Static huffman block (0b01)
outbits(state, 3, 3);
}
void zlib_finish_block(struct Outbuf *out)
void uzlib_finish_block(uzlib_lz77_state_t *state)
{
outbits(out, 0, 7); /* close block */
outbits(out, 0, 7); /* Make sure all bits are flushed */
// Close block (0b0000000)
// Make sure all bits are flushed (0b0000000)
outbits(state, 0, 14);
}

43
lib/uzlib/defl_static.h
View File

@ -1,43 +0,0 @@
/*
* Copyright (c) uzlib authors
*
* This software is provided 'as-is', without any express
* or implied warranty. In no event will the authors be
* held liable for any damages arising from the use of
* this software.
*
* Permission is granted to anyone to use this software
* for any purpose, including commercial applications,
* and to alter it and redistribute it freely, subject to
* the following restrictions:
*
* 1. The origin of this software must not be
* misrepresented; you must not claim that you
* wrote the original software. If you use this
* software in a product, an acknowledgment in
* the product documentation would be appreciated
* but is not required.
*
* 2. Altered source versions must be plainly marked
* as such, and must not be misrepresented as
* being the original software.
*
* 3. This notice may not be removed or altered from
* any source distribution.
*/
/* This files contains type declaration and prototypes for defl_static.c.
They may be altered/distinct from the originals used in PuTTY source
code. */
struct Outbuf {
void *dest_write_data;
void (*dest_write_cb)(void *data, uint8_t byte);
unsigned long outbits;
int noutbits;
};
void zlib_start_block(struct Outbuf *ctx);
void zlib_finish_block(struct Outbuf *ctx);
void zlib_literal(struct Outbuf *ectx, unsigned char c);
void zlib_match(struct Outbuf *ectx, int distance, int len);

14
lib/uzlib/lz77.c
View File

@ -11,6 +11,8 @@
#include "uzlib.h"
#include "defl_static.c"
#define MATCH_LEN_MIN (3)
#define MATCH_LEN_MAX (258)
@ -18,8 +20,8 @@
// hist_max should be greater than 0 a power of 2 (ie 1, 2, 4, 8, ...).
// It's possible to pass in hist=NULL, and then the history window will be taken from the
// src passed in to uzlib_lz77_compress (this is useful when not doing streaming compression).
void uzlib_lz77_init(struct uzlib_lz77_state *state, uint8_t *hist, size_t hist_max) {
memset(&state->outbuf, 0, sizeof(state->outbuf));
void uzlib_lz77_init(uzlib_lz77_state_t *state, uint8_t *hist, size_t hist_max) {
memset(state, 0, sizeof(uzlib_lz77_state_t));
state->hist_buf = hist;
state->hist_max = hist_max;
state->hist_start = 0;
@ -30,7 +32,7 @@ void uzlib_lz77_init(struct uzlib_lz77_state *state, uint8_t *hist, size_t hist_
// Search back in the history for the maximum match of the given src data,
// with support for searching beyond the end of the history and into the src buffer
// (effectively the history and src buffer are concatenated).
static size_t uzlib_lz77_search_max_match(struct uzlib_lz77_state *state, const uint8_t *src, size_t len, size_t *longest_offset) {
static size_t uzlib_lz77_search_max_match(uzlib_lz77_state_t *state, const uint8_t *src, size_t len, size_t *longest_offset) {
size_t longest_len = 0;
for (size_t hist_search = 0; hist_search < state->hist_len; ++hist_search) {
size_t match_len;
@ -55,7 +57,7 @@ static size_t uzlib_lz77_search_max_match(struct uzlib_lz77_state *state, const
}
// Compress the given chunk of data.
void uzlib_lz77_compress(struct uzlib_lz77_state *state, const uint8_t *src, unsigned len) {
void uzlib_lz77_compress(uzlib_lz77_state_t *state, const uint8_t *src, unsigned len) {
const uint8_t *top = src + len;
while (src < top) {
// Look for a match in the history window.
@ -64,10 +66,10 @@ void uzlib_lz77_compress(struct uzlib_lz77_state *state, const uint8_t *src, uns
// Encode the literal byte or the match.
if (match_len == 0) {
zlib_literal(&state->outbuf, *src);
uzlib_literal(state, *src);
match_len = 1;
} else {
zlib_match(&state->outbuf, match_offset, match_len);
uzlib_match(state, match_offset, match_len);
}
// Push the bytes into the history buffer.

18
lib/uzlib/uzlib.h
View File

@ -42,8 +42,6 @@
#include <stdint.h>
#include <stdbool.h>
#include "defl_static.h"
#include "uzlib_conf.h"
#if UZLIB_CONF_DEBUG_LOG
#include <stdio.h>
@ -135,16 +133,22 @@ int uzlib_parse_zlib_gzip_header(uzlib_uncomp_t *d, int *wbits);
/* Compression API */
struct uzlib_lz77_state {
struct Outbuf outbuf;
typedef struct {
void *dest_write_data;
void (*dest_write_cb)(void *data, uint8_t byte);
unsigned long outbits;
int noutbits;
uint8_t *hist_buf;
size_t hist_max;
size_t hist_start;
size_t hist_len;
};
} uzlib_lz77_state_t;
void uzlib_lz77_init(struct uzlib_lz77_state *state, uint8_t *hist, size_t hist_max);
void uzlib_lz77_compress(struct uzlib_lz77_state *state, const uint8_t *src, unsigned len);
void uzlib_lz77_init(uzlib_lz77_state_t *state, uint8_t *hist, size_t hist_max);
void uzlib_lz77_compress(uzlib_lz77_state_t *state, const uint8_t *src, unsigned len);
void uzlib_start_block(uzlib_lz77_state_t *state);
void uzlib_finish_block(uzlib_lz77_state_t *state);
/* Checksum API */